Biology (Evolution) Chapter 1

Front 1

"Kingdom Monera"

Back 1

Now we know that there are two distinct lineages of prokaryotic organisms:

Domain Archaea (the Archaebacteria)
Domain Bacteria ("true" bacteria)

Front 2

Archaea and Bacteria

Back 2

considered to be "prokaryotic"--pre-nuclear. They lack membrane bounded organelles or nuclei, though many do have internal membrane systems.

Front 3

Domain Archaea

Back 3

includes organisms that can withstand the most extreme environments of any living thing known. They are not classified on the basis of common descent (as far as we know), but rather are placed into form taxa that reflect their metabolic strategies (which do not necessarily represent physiological homologies).

Front 4

methanogens

Back 4

methane-generating archaeans

Front 5

thermophiles

Back 5

archaeans living in extremely hot environments (e.g., sulfur hotsprings, deep sea hydrothermal vent communities

Front 6

halophiles

Back 6

archaeans living in extremely salty environments

Front 7

Bacterial Structure and Function

Back 7

Bacteria may be categorized (but not classified) on the basis of shape:
round (cocci)
rod-shaped (bacilli)
helix (spirillae and spirochaetes - superficially similar only)

Front 8

clustering bacteria may be given the prefix ?

Back 8

staphyl

Front 9

A link-forming bacteria may be given the prefix

Back 9

"strept-"

Front 10

Bacterial shapes______?

Back 10

do not necessarily reflect phylogenetic relationships; there may be
-convergence (e.g., spirillum & spirochete)
-a diversity of shapes in closely related bacteria (e.g. spirillum & vibrio)

Front 11

Bacteria Size:

Back 11

range in size from 1-5 micrometers--much smaller than most eukaryotic cells (100-1000 micrometers)

Front 12

Bacterial genome consists of what?

Back 12

a single, circular chromosome of double-stranded DNA. This can be very large, and is organized in the nucleoid region of the cell.

Front 13

Average Bacterium:

Back 13

has about 1000 genes.

Front 14

some bacteria contain plasmids, what are plasmids?

Back 14

small, circular pieces of autonomously replicating DNA. A plasmid usually contains only a few genes, and is not considered part of the bacterium's genome. However, it may confer phenotypic traits (e.g., antibiotic resistance or the ability to produce toxins) on the host bacterium.

Front 15

Two major types of cell wall can be distinguished with ____?

Back 15

Gram Staining

Front 16

The major difference is the amount and location of a mucopolysaccharide known as___? This question is in relation to cell wall...

Back 16

peptidoglycan

Front 17

Peptidoglycan

Back 17

forms a thick, rigid layer in both Gram positive (G+) and Gram negative (G-) cells. It composed of an overlapping lattice of two sugars crosslinked by amino acid "bridges".

Front 18

Peoptidoglycan

Back 18

The two sugars are N-acetyl glucosamine (NAG) and N-acetyl muramic acid (NAM). NAM is found ONLY in bacterial cell walls--nowhere else.

Front 19

Gram Positive:

Back 19

stain dark with Gram method
G+ have a very thick external layer of peptidoglycan

Front 20

Gram Negative:

Back 20

do not stain with Gram method (appear pink from safranin counterstain)
G- have a thin layer of peptidoglycan sandwiched between two plasma membranes (inner and outer)

Front 21

Gram staining properties are linked to pathogenicity

Back 21

with G- often being more dangerous than G+.

Front 22

Because the peptidoglycan layer of G- is protected by a plasma membrane, it is less susceptible to ____?

Back 22

attack by antibiotics which interfere with the formation of peptidoglycan amino acid "bridge" bonds (e.g., penicillins)

Front 23

pilus

Back 23

is a surface extension from a bacterial cell that may act as a bridge between bacteria (for exchange of genetic material), or a means of attachment to a substrate or a host cell.

Front 24

Many bacteria are motile, what does motile mean?

Back 24

(they can move), and the means of locomotion is another way to identify them.

Front 25

flagellum

Back 25

(composed of unique protein known as flagellin)
Note the difference between the prokaryotic and eukaryotic flagella: Prokaryotes spins, Eukaryote waves.

Front 26

taxis means__?

Back 26

"movement" Bacteria exhibit various forms of positive or negative taxis, depending on species and specific environmental conditions. (e.g. phototaxis, chemotaxis, etc.)

Front 27

External to the cell wall, some species have a gel capsule , this gel capsules often functions in being __?

Back 27

protective against predators (or a host's immune system).

Front 28

Bacteria may reproduce asexually:

Back 28

binary fission

Front 29

Bacteria may also reproduce sexually:

Back 29

-conjugation (via pilus)
-transformation (uptake of bacterial genes from environment)
-transduction (insertion of bacterial genes by virus)

Front 30

Bacterial cells can be grown in culture on appropriate nutrient media (usually agar with broth added). A bacterial colony on an agar plate is called ______?

Back 30

a lawn, and various species have characteristic lawn phenotypes.

Front 31

Some species can form environmentally resistant structures called _____?

Back 31

Endospores, which is little more than the chromosome surrounded by a thick wall. It's nearly impossible to kill an endospore, so pathogens that can form them are particularly pernicious!

Front 32

Antibiotics

Back 32

are substances that inhibit the growth of prokaryotic cells. They are manufactured not only by plants and fungi, but also by some bacteria.

Front 33

Three basic types of organisms re: oxygen tolerance/metabolism:

Back 33

1)oblicate anaerobe - can do only fermentation; killed by oxygen
2)obligate aerobe - operates primarily on aerobic metabolism; cannot survive long without oxygen.
3)facultative anaerobe - can do either aerobic respiration or fermentation, depending on environmental conditions.

Front 34

In the Krebs Cycle, the terminal electron acceptor can be____?

Back 34

-oxygen (in aerobes)
-nitrate or nitrite (in denitrifying bacteria, which return nitrogen gas to the atmosphere)
-sulfate (in sulfur bacteria)

Front 35

Four Main Categories of Prokaryotic Energy Transduction?

Back 35

1) Photoautotrophs
2) Chemoautotrophs
3) Photoheterotrophs
4) Chemoheterotrophs

Front 36

Photoautotrophs

Back 36

-photosynthetic
-use CO2 as carbon source
-use light as Energy source
-cyanobacteria are the most common in this group

Front 37

Chemoautotrophs

Back 37

-chemosynthetic
-use CO2 as carbon source
-use inorganic compound oxidation as Energy source (e.g., H2, ammonia or iron ions)
-many archaebacteria fall into this category

Front 38

Photoheterotrophs

Back 38

-photosynthetic
-use organic molecules as a carbon source
-use light as energy source
-relatively few bacteria in this group

Front 39

Chemoheterotrophs

Back 39

-heterotrophic
-obtain energy from organic compounds
-vast majority of bacteria are in this category, along with most protists, animals, fungi and some plants.

Front 40

saprobe

Back 40

is a chemoheterotroph that breaks down decaying organic matter for energy.

Front 41

parasite

Back 41

is a chemoheterotroph that uses the organic molecules of living tissue for energy

Front 42

How did it all begin?

Back 42

-Early hypotheses about the origin of bacterial metabolism suggested that the earliest cells used ATP from the "primordial soup".
-Problem: it's not likely there was enough ATP out there to fuel those newly made cells. ATP is highly unstable, and won't remain in solution for long.
-More plausible is the idea that CO2 was the first Carbon source, and that early cells had plasma-membrane anchored enzymes that could oxidize inorganic compounds to make the energy needed to drive synthesis of carbon compounds.

Front 43

Ecological Importance of Prokaryotes

Back 43

Along with fungi, they are the biosphere's main decomposers.
-Many are symbiotic
-parasitic (pathogens, opportunistic and not)
-mutualistic
-commensal

Front 44

symbiotic:

Back 44

The term symbiosis (from the Greek sym, meaning "together" and bios, meaning "life") refers to the members of two different species (i.e., two populations) having some sort of ecological interaction that affects both populations.

Front 45

coevolution.

Back 45

When two species evolve in response to each other's activities

Front 46

-, +, 0 signs in symbiosis

Back 46

"+" means that the population benefits from the interaction

"-" means that the population is harmed by the interaction

"0" means that the population is not affected by the interaction

Front 47

Obligate Mutualism:

Back 47

Neither organism can survive without the other.

Front 48

Protocooperation

Back 48

The Clown Fish and its Sea Anemone partner both benefit from the relationship: Nemo gets a safe home that protects him from predators, and he fiercely protects his sea anemone from predators. He also feeds the anemone. How cute is that?

Front 49

resource partitioning.

Back 49

two species vie for habitat and food resources, and it appears that the exotic Brown Anole has displaced the native Green Anole in some physical spaces, such as lower shrubbery and grass. The Green Anole generally lives higher up in the trees and foliage than the Brown Anole does.

Front 50

Neutralism

Back 50

In a case of true neutralism, two populations interact, but neither would have any effect on the evolutionary fitness of the other.

Front 51

Predation

Back 51

This is possibly the most familiar type of symbiosis. The predator species (in the illustration below, the Lion (Panthera leo)) kills and consumes the prey species (in this case, a Cape Buffalo (Syncerus caffer).

Predation has driven the evolution of some truly amazing phenomena, such as crypsis (camouflaging coloration), aposematism (warning coloration), mimicry, and other ways animals avoid being eaten.

Front 52

crypsis

Back 52

camouflaging coloration

Front 53

aposematism

Back 53

warning coloration (poisonous or venomous species)

Front 54

mimicry

Back 54

a species has evolved the superficial appearance of something else

Front 55

Batesian Mimicry

Back 55

a harmless mimic looks like a poisonous model.

Front 56

Mullerian Mimicry

Back 56

several poisonous/distasteful species resemble one another.

Front 57

poisonous

Back 57

oxic when eaten or touched

Front 58

venomous

Back 58

delivers toxin with an apparatus such as a fang or stinger

Front 59

parasite

Back 59

an organism that takes up residence in or on a host organism and feeds on the host's body without killing it outright.

Front 60

definitive host.

Back 60

An organism that is host to an adult parasite
-The definitive host is usually a predator of the intermediate host, and the life cycle is completed when the definitive host eats the intermediate host, freeing the larval forms to take up residence, as shown below in the tapeworm life cycle.

Front 61

intermediate host

Back 61

An organism that is host to a juvenile parasite

Front 62

parasitoid

Back 62

acts as a parasite of its host until some critical point of its life cycle--such as metamorphosis from juvenile to adult or onset of reproduction--at which point it kills the host.

Front 63

Commensalism

Back 63

In this case, one species benefits from the presence of another, which is not affected by the presence of the first species.

Front 64

Amensalism

Back 64

Amensalism occurs when species A impedes the success of species B, but is neither positively nor negatively affected by the presence of the species B. This is commonly the effect when one species produces a chemical compound (as part of its normal metabolic reactions) that is harmful to the other species.

Front 65

Allelopathy

Back 65

ome plants produce chemical compounds that inhibit the growth of nearby would-be competitors, is one type of amensalistic interaction.

Front 66

The Importance of Nitrogen Metabolism

Back 66

Nitrogen fixation - conversion of atmospheric nitrogen to nitrogen compounds (ammonia, nitrite or nitrate) that are usable by plants

Denitrification - nitrate-->nitrite-->ammonia-->N2

Nitrosomonas spp. - converts ammonia to nitrite

Pseudomonas spp. - converts nitrite or nitrate into N2 (denitrification)

Front 67

pathogen

Back 67

disease causing agent

Front 68

Pseudomonas

Back 68

common bacteria are very common in the environment, they usually do not cause disease. However, in an immunocompromised animal, they can proliferate, creating a very difficult-to-treat infection. Many strains are resistant to a wide variety of antibiotics.) Hence, they are considered opportunistic pathogens.

Front 69

Koch's Postulates, In order for a microorganism to be declared the cause of a particular disease, however, it must meet the following criteria:

Back 69

1)it must be isolated from a diseased individual
2)it must be grown in pure culture from that sample
3)it must cause the disease in a healthy individual when introduced from that culture
4)it must be isolated from the newly infected individual

Front 70

How does bacteria cause diseases?

Back 70

1) Invasion of Tissues
2)Exotoxins
3) Endotoxins
4) Iatrogenic infection
5) Bacteriostatic
6) Bacteriocidal
7) sometimes even from antibiotics

Front 71

exotoxins

Back 71

(secreted into the medium in which the bacterium lives)
-Clostridium spp.
-Escherichia coli
-Vibrio cholerae

Front 72

endotoxins

Back 72

(part of plasma membrane (primarily in G- bacteria)
-Salmonella spp.

Front 73

iatrogenic infection

Back 73

one that is caused by the place of healing or the healer.

Front 74

bacteriostatic

Back 74

a drug which inhibits the growth of bacterial culture.

Front 75

bacteriocidal

Back 75

a drug which kills bacteria outright.